Using street view, you can often see "Social Security" on a building or sign.

Social Security Office Directions and Notes :

D57 IS ON ROCKAWAY PKWY BETWEEN AVE M + AVE N IN THE PARKWAY SHOPPING CENTER. TAKE THE L TRAIN TO THE LAST STOP,TRANSFER TO THE 42 BUS TOWARD CANARSIE PIER). NEW SOCIAL SECURITY CARDS REQUIRE AN IN PERSON VISIT TO BROOKLYN SOCIAL SECURITY CARD CENTER (782) 625 FULTON ST 6TH FLR BROOKLYN NY 11201 (M-F 7AM-4:30PM + THURS 7AM-7:00PM) NOTE: REQUESTS FOR REPLACEMENT SSN CARDS NO LONGER REQUIRE AN IN-OFFICE INTERVIEW + CAN BE MAILED TO THE CARD CENTER.

Brooklyn Social Security Office Notes

Social Security Card Centers
If you live in the Brooklyn or Queens area, you may need to go to a 'card center'
instead of a 'field office'. Card centers are centralized processing
sites for all Social Security number applications for area residents.
You must visit a card center if you need a Social Security card,
your personal information needs updating, or your employer asked you
to visit a Social Security office.

For other needs (ex. applying for benefits) you may visit the field
office listed above.

Hours of Social Security offices were reduced in November, 2012.
Almost all Social Security offices in the continental US have hours
of 9:00 to noon on Wednesdays, and 9:00 to 4:00 on other weekdays.
See if you can get an appointment by phone. Fridays may be less
crowded. You can do things like signup for Medicare
online at ssa.gov.

You can also qualify through a spouse's work record, or even through your current job :

Most people 65 or older are eligible for Medicare hospital insurance (Part A) based on their own—or their spouse's— employment. You are eligible at 65 if you:

Receive Social Security or railroad retirement benefits;

Are not getting Social Security or railroad retirement benefits, but you have worked long enough to be eligible for them;

Would be entitled to Social Security benefits based on your spouse's (or divorced spouse's) work record, and that spouse is at least 62 (your spouse does not have to apply for benefits in order for you to be eligible based on your spouse's work) ;or

Worked long enough in a federal, state, or local government job to be insured for Medicare.